mortgage_calculator

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

No annotations are provided, so the description carries the burden of behavioral disclosure. It adds useful context (currency-agnostic, optional DTI) but does not explicitly state that the tool is a pure calculation with no side effects, nor does it mention the output format or edge-case handling. This is sufficient for a simple calculator but not fully transparent.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Two sentences, front-loaded with the primary purpose. No redundant information; every sentence adds value (purpose and optional DTI behavior). Excellent conciseness.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a simple calculator with no output schema, the description adequately covers return values (monthly payment, total interest, and DTI if monthly_income provided) and adds the currency-agnostic behavior. Missing edge-case handling or exact output structure, but this is not critical for a straightforward calculator.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so the baseline is 3. The description adds the 'currency-agnostic' context, but does not add meaning beyond the schema for individual parameters. The mention that monthly_income enables DTI is already present in the schema description.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states a specific action ('Estimate a monthly mortgage payment and total interest') and resource, distinguishing it from sibling tools like search_listings or get_market_summary. The purpose is unambiguous and immediately understandable.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description implies usage (estimate mortgage payments) but does not explicitly state when to use this tool versus alternatives or when not to use it. The only guideline is the optional monthly_income parameter for DTI, which is more parameter-specific than tool-selection guidance.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.